Full-field polarimetric image (same as in Fig. 1, Q_ϕ × r²) displayed in panel a, on top of which several structures previously detected are overlaid: Hashimoto et al. (2011) spirals (orange lines), out of plane accreting spirals from Tang et al. (2012; blue lines), and the dust ring (yellow ellipses) from the 0.9 mm ALMA image (Tang et al. 2017). The inner spiral arms (S1_CO, S2_CO) detected by Tang et al. (2017) are superimposed to the SPHERE polarimetric image Q_ϕ, further processed with a gradient algorithm to enhance the inner spirals (b), and the ALMA CO map (c), in a 2″ field of view. Features f1 and f2 are discussed in Sect. 4. North is up, east is left.